APPARATUS FOR ATTENUATING VIBRATION OF A TUBULAR MEMBER

摘要

The apparatus includes a cable (240) disposed in the tubular member (40) and a plurality of spaced-apart attenuating assemblies (250) mounted on the cable for frictionally engaging the wall of the tubular member. Each attenuating assembly comprises two spaced-apart end fittings (260, 280) mounted on the cable. Interposed between the end fittings is a heat vaporisable insert (340) for maintaining the end fittings in their spaced-apart relationship until the insert vaporizes. A preloaded coiled spring (360), which interconnects the end fittings and surrounds the insert, biases the end fittings towards each other after the insert vaporizes. A tubular, flexible and braided sheath (390), which is interposed between the end fittings, surrounds the spring and has respective ends thereof attached to the end fittings. When the insert vaporizes, the spring biases the end fittings closer together, thereby axially shortening the sheath. The braided sheath radially expands as it axially shortens and frictionally contracts the inner wall of the tubular member to damp the tubular member's vibrations.